Hammer

ABSTRACT

The various embodiments disclosed and pictured illustrate a hammer for comminuting various materials. The embodiments pictured and described herein are primarily for use with a rotatable hammermill assembly. The hammer includes a connector end having a rod hole therein, a contact end for delivery of energy to the material to be comminuted, and a neck affixing the connector end to the contact end. The neck is formed with at least one neck recess therein. In other embodiments, one or more shoulders are positioned around the periphery of the rod hole for added strength. In still other embodiments, the contact end is configured with more than one contact surface.

CROSS REFERENCE TO RELATED APPLICATIONS

Applicant states that this utility patent application claims priorityfrom and is a continuation in part of U.S. patent application Ser. No.12/882,422, which patent application is a continuation of U.S. patentapplication Ser. No. 12/398,007 and claims priority therefrom, whichapplication is a continuation-in-part of U.S. patent application Ser.No. 11/897,586 filed on Aug. 31, 2007, which application is acontinuation-in-part of U.S. patent application Ser. No.11/544,526 (nowU.S. Pat. No. 7,559,497) filed on Oct. 6, 2006, which application is acontinuation-in-part of U.S. patent application Ser. No. 11/150,430 now(U.S. Pat. No. 7,140,569) filed on Jun. 11, 2005, which was acontinuation-in-part of U.S. patent application Ser. 10/915,750 filed onAug. 11, 2004, now abandoned, all of which are incorporated by referenceherein in their entireties. Applicant also claims priority fromprovisional U.S. patent application Ser. No. 61/257,958 filed on Nov. 4,2009.

FIELD OF INVENTION

This invention relates generally to a device for comminuting or grindingmaterial. More specifically, the invention is especially useful for useas a hammer in a rotatable hammermill assembly.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

No federal funds were used to develop or create the invention disclosedand described in the patent application.

REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTINGCOMPACT DISK APPENDIX

Not Applicable

BACKGROUND

A number of different industries rely on impact grinders or hammermillsto reduce materials to a smaller size. For example, hammermills areoften used to process forestry and agricultural products as well as toprocess minerals, and for recycling materials. Specific examples ofmaterials processed by hammermills include grains, animal food, petfood, food ingredients, mulch and even bark. This invention although notlimited to grains, has been specifically developed for use in the grainindustry. Whole grain corn essentially must be cracked before it can beprocessed further. Dependent upon the process, whole corn may be crackedafter tempering yet before conditioning. A common way to carry outparticle size reduction is to use a hammermill where successive rows ofrotating hammer like devices spinning on a common rotor next to oneanother comminute the grain product. For example, methods for sizereduction as applied to grain and animal products are described inWatson, S. A. & P. E. Ramstad, ed. (1987, Corn: Chemistry andTechnology, Chapter 11, American Association of Cereal Chemist, Inc.,St. Paul, Minn.), the disclosure of which is hereby incorporated byreference in its entirety. The application of the invention as disclosedand herein claimed, however, is not limited to grain products or animalproducts.

Hammermills are generally constructed around a rotating shaft that has aplurality of disks provided thereon. A plurality of free-swinginghammers are typically attached to the periphery of each disk usinghammer rods extending the length of the rotor. With this structure, aportion of the kinetic energy stored in the rotating disks istransferred to the product to be comminuted through the rotatinghammers. The hammers strike the product, driving into a sized screen, inorder to reduce the material. Once the comminuted product is reduced tothe desired size, the material passes out of the housing of thehammermill for subsequent use and further processing. A hammer mill willbreak up grain, pallets, paper products, construction materials, andsmall tree branches. Because the swinging hammers do not use a sharpedge to cut the waste material, the hammer mill is more suited forprocessing products which may contain metal or stone contaminationwherein the product the may be commonly referred to as “dirty”. A hammermill has the advantage that the rotatable hammers will recoil backwardlyif the hammer cannot break the material on impact. One significantproblem with hammer mills is the wear of the hammers over a relativelyshort period of operation in reducing “dirty” products which includematerials such as nails, dirt, sand, metal, and the like. As found inthe prior art, even though a hammermill is designed to better handle theentry of a “dirty” object, the possibility exists for catastrophicfailure of a hammer causing severe damage to the hammermill andrequiring immediate maintenance and repairs.

Hammermills may also be generally referred to as crushers—whichtypically include a steel housing or chamber containing a plurality ofhammers mounted on a rotor and a suitable drive train for rotating therotor. As the rotor turns, the correspondingly rotating hammers comeinto engagement with the material to be comminuted or reduced in size.Hammermills typically use screens formed into and circumscribing aportion of the interior surface of the housing. The size of theparticulate material is controlled by the size of the screen aperturesagainst which the rotating hammers force the material. Exemplaryembodiments of hammermills are disclosed in U.S. Pat. Nos. 5,904,306;5,842,653; 5,377,919; and 3,627,212.

The four metrics of strength, capacity, run time and the amount of forcedelivered are typically considered by users of hammermill hammers toevaluate any hammer to be installed in a hammermill. A hammer to beinstalled is first evaluated on its strength. Typically, hammermillmachines employing hammers of this type are operated twenty-four hours aday, seven days a week. This punishing environment requires strong andresilient material that will not prematurely or unexpectedlydeteriorate. Next, the hammer is evaluated for capacity, or morespecifically, how the weight of the hammer affects the capacity of thehammermill. The heavier the hammer, the fewer hammers that may be usedin the hammermill by the available horsepower. A lighter hammer thenincreases the number of hammers that may be mounted within thehammermill for the same available horsepower. The more force that can bedelivered by the hammer to the material to be comminuted against thescreen increases effective comminution (i.e. cracking or breaking downof the material) and thus the efficiency of the entire comminutionprocess is increased. In the prior art, the amount of force delivered isevaluated with respect to the weight of the hammer.

Finally, the length of run time for the hammer is also considered. Thelonger the hammer lasts, the longer the machine run time, the largerprofits presented by continuous processing of the material in thehammermill through reduced maintenance costs and lower necessary capitalinputs. The four metrics are interrelated and typically tradeoffs arenecessary to improve performance. For example, to increase the amount offorce delivered, the weight of the hammer could be increased. However,because the weight of the hammer increased, the capacity of the unittypically will be decreased because of horsepower limitations. There isa need to improve upon the design of hammermill hammers available in theprior art for optimization of the four (4) metrics listed above.

Free-Swinging Hammermill Assemblies

Rotatable hammermill assemblies as found in the prior art, which arewell known and therefore not pictured herein, generally includes two endplates on each end with at least one interior plate positioned betweenthe two end plates. The end plates include an end plate drive shaft holeand the interior plates include an interior plate drive shaft hole. Ahammermill drive shaft passes through the end plate drive shaft holesand the interior plate drive shaft holes. The end plates and interiorplates are affixed to the hammermill drive shaft and rotatabletherewith.

Each end plate also includes a plurality of end plate hammer rod holes,and each interior plate includes a plurality of interior plate hammerrod holes. A hammer rod passes through corresponding end plate hammerrod holes and interior plate hammer rod holes. A plurality of hammers ispivotally mounted to each hammer rod. The hammers are typically orientedin rows along each hammer rod, and each hammer rod is typically orientedparallel to one another and to the hammermill drive shaft.

The hammermill assembly and various elements thereof rotate about thelongitudinal axis of the hammermill drive shaft. As the hammermillassembly rotates, centrifugal force causes the hammers to rotate aboutthe hammer rod to which each hammer is mounted. Free-swinging hammersare often used instead of rigidly connected hammers in case lodgedmetal, foreign objects, or other non-crushable material enters thehousing with the particulate material to be reduced, which material maybe a cereal grain

For effective comminution in hammermill assemblies using free-swinginghammers, the rotational speed of the hammermill assembly must producesufficient centrifugal force to hold the hammers as close to the fullyextended position as possible when material is being communited.Depending on the type of material being processed, the minimum hammertip speeds of the hammers are usually 5,000 to 11,000 feet per minute(FPM). In comparison, the maximum speeds depend on shaft and bearingdesign, but usually do not exceed 30,000 FPM. In special high-speedapplications, the hammermill assemblies may be configured to operate upto 60,000 FPM.

In the case of disassembly for the purposes of repair and replacement ofworn or damaged parts, the wear and tear causes considerable difficultyin realigning and reassembling the various elements of the hammermillassembly. Moreover, the elements of the hammermill assembly aretypically keyed to one another, or at least to the hammermill driveshaft, which further complicates the assembly and disassembly process.For example, the replacement of a single hammer may require disassemblyof the entire hammermill assembly. Given the frequency at which wearparts require replacement, replacement and repairs constitute anextremely difficult and time consuming task that considerably reducesthe operating time of the size reducing machine.

Applicant is the inventor on various other patents and patentapplications relating to hammers for use in comminuting materials.Accordingly, U.S. Pat. Nos. 7,140,569; 7,559,497; and 7,621,477 and U.S.Pub. App. No. 2009/0224090 are incorporated by reference herein in theirentireties.

Although not shown in detail herein, one of ordinary skill willappreciate that the present art may be applied to the designs andinventions protected by patents held by Applicant or others withoutlimitation, dependent only upon a particular need or application,including:

Patent Number Title D588,174 Hammermill hammer D573,163 Hammermillhammer D555,679 Hammermill hammer D552,639 Hammermill hammer D551,267Hammermill hammer D551,266 Hammermill hammer D550,728 Hammermill hammerD545,847 Hammermill hammer D545,846 Hammermill hammer D545,328Hammermill hammer D545,327 Hammermill hammer D544,504 Hammermill hammerD544,503 Hammermill hammer D536,352 Hammermill hammer D536,351Hammermill hammer D536,350 Hammermill hammer

The preceding cited patents are incorporated by reference herein intheir entireties.

BRIEF DESCRIPTION OF THE FIGURES

In order that the advantages of the invention will be readilyunderstood, a more particular description of the invention brieflydescribed above will be rendered by reference to specific embodimentsillustrated in the appended drawings. Understanding that these drawingsdepict only typical embodiments of the invention and are not thereforeto be considered limited of its scope, the invention will be describedand explained with additional specificity and detail through the use ofthe accompanying drawings.

FIG. 1 provides a perspective view of the internal configuration of ahammer mill at rest as commonly found in the prior art.

FIG. 2 provides a perspective view of the internal configuration of ahammermill during operation as commonly found in the prior art.

FIG. 3 provides an exploded perspective view of a hammermill as found inthe prior art as shown in FIG. 1.

FIG. 4 provides an enlarged perspective view of the attachment methodsand apparatus as found in the prior art and illustrated in FIG. 3.

FIG. 5 provides a perspective view of a first embodiment of a notchedhammer.

FIG. 6 provides a top view of the first embodiment of a notched hammer.

FIG. 7 provides a detailed perspective view of the rod hole of the firstembodiment of a notched hammer.

FIG. 8 provides a perspective view of a second embodiment of a notchedhammer.

FIG. 9 provides a perspective view of a third embodiment of a notchedhammer.

FIG. 10 provides a perspective view of a fourth embodiment of a notchedhammer.

FIG. 11 provides a perspective view of a fifth embodiment of a notchedhammer.

FIG. 12 provides a perspective view of a sixth embodiment of a notchedhammer.

FIG. 13 provides a perspective view of a seventh embodiment of a notchedhammer.

FIG. 14 provides a perspective view of an eighth embodiment of a notchedhammer.

FIG. 15 provides a perspective view of a ninth embodiment of a notchedhammer.

FIG. 16 provides a perspective view of a first embodiment of a multipleblade hammer.

FIG. 17 provides a top view of the first embodiment of a multiple bladehammer.

FIG. 18 provides a perspective view of a second embodiment of a multipleblade hammer.

FIG. 19 provides a perspective view of one embodiment of a dual-bladehammer.

FIG. 20 provides a front view of one embodiment of the dual-bladehammer.

FIG. 21 provides a side view of one embodiment of the dual-blade hammer.

FIG. 22 provides a second perspective view of one embodiment of thedual-blade hammer.

DETAILED DESCRIPTION—LISTING OF ELEMENTS

ELEMENT DESCRIPTION ELEMENT NUMBER Hammermill assembly  2 Hammermildrive shaft  3 End plate  4 End plate drive shaft hole  5a End platehammer rod hole  5b Interior plate  6 Interior plate drive shaft hole 7a Interior plate hammer rod hole  7b Hammer rod  8 Spacer  8a Hammer(prior art)  9 Hammer body (prior art)  9a Hammer contact edge (priorart)  9b Hammer rod hole (prior art)  9c Notched hammer  10 Notchedhammer neck  11 Neck void  11a Notched hammer first end  12 Notchedhammer first shoulder  14a Notched hammer second shoulder  14b Notchedhammer rod hole  15 Rod hole notch  15a Notched hammer second end  16Hardened contact edge  20 First contact surface  22a First contact point 22b Second contact surface  24a Second contact point  24b Third contactsurface  26a Third contact point  26b Fourth contact point  28 Edgepocket  29 Multiple blade hammer  30 Multiple blade hammer neck  31Multiple blade hammer first end  32 Multiple blade hammer first shoulder 34a Multiple blade hammer second shoulder  34b Multiple blade hammerrod hole  35 Multiple blade hammer second end  36 First blade  37aSecond blade  37b Third blade  37c Blade edge  38 Dual-blade hammer 110Connector end 120 Rod hole 122 First shoulder 124a Second shoulder 124bNotch 126 Neck 130 Neck first end 132 Neck second end 134 Neck recess136 Neck edge 138 Contact end 140 First contact surface 142a Secondcontact surface 142b Interstitial area 144

DETAILED DESCRIPTION—EXEMPLARY EMBODIMENTS

Before the various embodiments of the present invention are explained indetail, it is to be understood that the invention is not limited in itsapplication to the details of construction and the arrangements ofcomponents set forth in the following description or illustrated in thedrawings. The invention is capable of other embodiments and of beingpracticed or of being carried out in various ways. Also, it is to beunderstood that phraseology and terminology used herein with referenceto device or element orientation (such as, for example, terms like“front”, “back”, “up”, “down”, “top”, “bottom”, and the like) are onlyused to simplify description of the present invention, and do not aloneindicate or imply that the device or element referred to must have aparticular orientation. In addition, terms such as “first”, “second”,and “third” are used herein and in the appended claims for purposes ofdescription and are not intended to indicate or imply relativeimportance or significance. Furthermore, any dimensions recited orcalled out herein are for exemplary purposes only and are not meant tolimit the scope of the invention in any way unless so recited in theclaims.

DETAILED DESCRIPTION 1. Free-Swinging Hammermill Assemblies

Referring now to the drawings, wherein like reference numerals designateidentical or corresponding parts throughout the several views, FIGS. 1-3show a hammermill assembly 2 as found in the prior art. The hammermillassembly 2 includes two end plates 4 on each end with at least oneinterior plate 6 positioned between the two end plates 4. The end plates4 include an end plate drive shaft hole 5 a and the interior plates 6include an interior plate drive shaft hole 7 a. A hammermill drive shaft3 passes through the end plate drive shaft holes 5 a and the interiorplate drive shaft holes 7 a. The end plates 4 and interior plates 6 areaffixed to the hammermill drive shaft and rotatable therewith.

Each end plate 4 also includes a plurality of end plate hammer rod holes5 b, and each interior plate 6 includes a plurality of interior platehammer rod holes 7 b. A hammer rod 8 passes through corresponding endplate hammer rod holes 5 b and interior plate hammer rod holes 7 b. Aplurality of hammers 9 are pivotally mounted to each hammer rod 8, whichis shown in detail in FIG. 4. The hammers 9 are typically oriented inrows along each hammer rod 8, and each hammer rod 8 is typicallyoriented parallel to one another and to the hammermill drive shaft 3.

Each hammer 9 includes a hammer body 9 a, hammer contact edge 9 b, and ahammer rod hole 9 c passing through the hammer body 9 a, which is shownin detail in FIG. 4. Each hammer rod 8 passes through the hammer rodhole 9 c of at least one hammer 9. Accordingly, the hammers 9 pivot withrespect to the hammer rod 8 to which they are attached about the centerof the hammer rod hole 9 c. A spacer 8 a may be positioned around thehammer rod 8 and between adjacent hammers 9 or adjacent hammers 9 andplates 4,6 to better align the hammers 9 and/or plates 4, 6, which isbest shown in FIGS. 3-4. As is well known to those of skill in the art,a lock collar (not shown) would typically be placed on the end of thehammer rod 8 to compress and hold the spacers 8 a and the hammers 9 inalignment. All these parts require careful and precise alignmentrelative to one another. This type of hammer 9, which is shown affixedto the hammermill assembly 2 shown in FIGS. 1-3 and separately in FIG.4, is commonly referred to as free-swinging hammers 9. Free-swinginghammers 9 are hammers 9 that are pivotally mounted to the hammermillassembly 9 in a manner as described above and are oriented outwardlyfrom the center of the hammermill assembly 2 by centrifugal force as thehammermill assembly 2 rotates.

The hammermill assembly 2 and various elements thereof rotate about thelongitudinal axis of the hammermill drive shaft 3. As the hammermillassembly 2 rotates, centrifugal force causes the hammers 9 to rotateabout the hammer rod 8 to which each hammer 9 is mounted. The hammermillassembly 2 is shown at rest in FIG. 1 and in a dynamic state in FIG. 2,as in operation. Free-swinging hammers 9 are often used instead ofrigidly connected hammers in case tramped metal, foreign objects, orother non-crushable material enters the housing with the particulatematerial to be reduced, such as grain.

For effective comminution in hammermill assemblies 2 using free-swinginghammers 9, the rotational speed of the hammermill assembly 2 mustproduce sufficient centrifugal force to hold the hammers 9 as close tothe fully extended position as possible when material is beingcommunited. Depending on the type of material being processed, theminimum hammer tip speeds of the hammers are usually 5,000 to 11,000feet per minute (“FPM”). In comparison, the maximum speeds depend onshaft and bearing design, but usually do not exceed 30,000 FPM. Inspecial high-speed applications, the hammermill assemblies 2 may beconfigured to operate up to 60,000 FPM.

In the case of disassembly for the purposes of repair and replacement ofworn or damaged parts, the wear and tear causes considerable difficultyin realigning and reassembling the various elements of the hammermillassembly 2. Moreover, the elements of the hammermill assembly 2 aretypically keyed to one another, or at least to the hammermill driveshaft 3, which further complicates the assembly and disassembly process.For example, the replacement of a single hammer 9 may requiredisassembly of the entire hammermill assembly 2. Given the frequency atwhich wear parts require replacement, replacement and repairs constitutean extremely difficult and time consuming task that considerably reducesthe operating time of the size reducing machine. Removing a singledamaged hammer 9 may take in excess of five (5) hours due to both thehammermill assembly 2 design and the realignment difficulties related tothe problems caused by impact of debris with the non-impact surfaces ofthe hammermill assembly 2.

Another problem found in the prior art hammermill assemblies 2 shown inFIGS. 1-3 is exposure of a great deal of the surface area of thehammermill assembly 2 elements to debris. The end plates 4 and interiorplates 6, spacers 8 a, and hammers 9 are all subjected to considerablecontact with the debris and material within the hammermill assembly 2.This not only creates excessive wear, but contributes to realignmentdifficulties by bending and damaging of the various elements of thehammermill assembly 2, which may be caused by residual impact. Thus,after a period of operation, prior art hammermill assemblies 2 becomeeven more difficult to disassemble and reassemble. The problems relatedto comminution service and maintenance of hammermill assemblies 2provides abundant incentive for improvement of hammers 9 to lengthenoperational run times.

2. Illustrative Embodiments of Notched Hammer

FIGS. 5-6 show a first embodiment of the notched hammer 10 for use in arotatable hammermill assembly 2, which type of hammermill assembly 2 waspreviously described herein. The notched hammer 10 is comprised of anotched hammer first end 12 (also referred to herein occasionally as thesecurement end) for securement within the hammermill assembly 2 and anotched hammer second end 16 (also referred to herein occasionally asthe contact end) for delivery of mechanical energy to and contact withthe material to be comminuted. The notched hammer first end 12 isconnected to the notched hammer second end 16 by a notched hammer neck11. A notched hammer rod hole 15 is centered in the notched hammer firstend 12 for engagement with and attachment of the notched hammer 10 tothe hammer rod 8 of a hammermill assembly 2. Typically, the distancefrom the center of the notched hammer rod hole 15 to the most distaledge of the notched hammer second end 16 is referred to as the “hammerswing length.”

As shown generally in FIGS. 5-6 and in detail in FIG. 7, at least onerod hole notch 15 a is formed in the notched hammer rod hole 15. The atleast one rod hole notch 15 a transverses the length of the notchedhammer rod hole 15 and is aligned with the notched hammer neck 11. Asshown in the various embodiments pictured and described herein, thelongitudinal axis of the rod hole notch 15 a is parallel with thelongitudinal axis of the notched hammer rod hole 15, but may havedifferent orientations in embodiments not pictured or described herein,such as an embodiment wherein the rod hole notch 15 a is not parallel tothe longitudinal axis of the notched hammer rod hole 15. Furthermore,the cross-sectional shape of the rod hold notch 15 a may be any shape,such as circular, oblong, angular, or any other shape known to thoseskilled in the art. Additionally, the cross-sectional shape of the rodhole notch 15 a may vary along its length.

As shown in FIGS. 5-7, the sides of the notched hammer neck 11 in firstembodiment of the notched hammer 10 are parallel, and the notched hammerrod hole 15 is surrounded by a notched hammer first shoulder 14 a. Thenotched hammer first shoulder 14 a is comprised of a raised, singleuniform ring surrounding the notched hammer rod hole 15. The notchedhammer first shoulder 14 a thereby increased the material thicknessaround the notched hammer rod hole 15 as compared to the thickness ofthe notched hammer first end 12. The notched hammer first shoulder 14 aincreases the surface area available for distribution of the opposingforces placed on the notched hammer rod hole 15 during operation in anamount proportional to the width of the hammer. This increase in surfacearea allows for a longer useful life of the notched hammer 10 becausethe additional surface area works to decrease the amount of elongationof the notched hammer rod hole 15 while still allowing the notchedhammer 10 to swing freely on the hammer rod 8 during operation. Otherembodiments of the notched hammer 10 may not be configured with anotched hammer first shoulder 14 a, and in still other embodiments thesides of the notched hammer neck 11 may be oriented other than parallelto one another.

The first embodiment of the notched hammer 10 also includes a hardenedcontact edge 20 welded on the periphery of the notched hammer second end16. The hardened contact edge 20 is positioned on the portion of thenotched hammer second end 16 that is most often in contact with thematerial to be comminuted during operation of the hammermill assembly 2.The hardened contact edge 20 may be comprised of any suitable materialknown to those skilled in the art, and it is contemplated that one suchmaterial is tungsten carbide. In other embodiments of the notched hammer10 a hardened contact edge 20 is not positioned on the notched hammersecond end 16.

A second embodiment of the notched hammer 10 is shown in FIG. 8. In thesecond embodiment the notched hammer neck 11 includes a plurality ofneck voids 11 a. As shown in FIG. 8, the second embodiment includes twoneck voids 11 a that are both circular in shape but have differentdiameters from one another. The neck voids 11 a may have any shape, andeach neck void 11 a may have a different shape than an adjacent neckvoid 11 a. Furthermore, neck voids 11 a may have perimeters of differingvalues, and the neck voids 11 a need not be positioned along the centerline of the notched hammer neck 11. More than two neck voids 11 a may beused in any the second embodiment of the notched hammer 10. The neckvoids 11 a may be asymmetrical or symmetrical. As shown in FIG. 8, thecircular nature of the neck voids 11 a allows the transmission anddissipation of the stresses produced at the notched hammer first end 12through and along the notched hammer neck 11.

The notched hammer neck 11 in the second embodiment is not as thick asthe notched hammer first end 12 or the notched hammer second end 16.This configuration of the notched hammer neck 11 allows for reduction inthe overall weight of the notched hammer 10, to which attribute the neckvoids 11 a also contribute. The mechanical energy imparted to thenotched hammer second end 16 with respect to the mechanical energyimparted to the notched hammer neck 11 is also increased with thisconfiguration. The neck voids 11 a also allow for greater agitation ofthe material to be comminuted during operation of the hammermillassembly 2.

A third embodiment of the notched hammer 10 is shown in FIG. 9. Thenotched hammer rod hole 15 in the third embodiment includes a notchedhammer first shoulder 14 a and a notched hammer second shoulder 14 boriented symmetrically around the notched hammer rod hole 15. Asexplained in detail above for the first embodiment of the notched hammer10, the first and second rod hole shoulders 14 a, 14 b allow the notchedhammer rod hole 15 to resist elongation. In the third embodiment, thenotched hammer second shoulder 14 b is of a greater axial dimension thanthe notched hammer first shoulder 14 a but of a lesser radial dimension,and both the notched hammer first and second shoulders 14 a, 14 b aresymmetrical with respect to the notched hammer rod hole 15. Thisconfiguration increases the useful life of the notched hammer 10 whilesimultaneously allowing for decreased weight thereof since the portionof the notched hammer first end 12 not formed as either the notchedhammer first or second shoulders 14 a, 14 b may be of the same thicknessas the notched hammer neck 11 and notched hammer second end 16. Thethird embodiment is also show with a hardened contact edge 20 welded tothe notched hammer second end 16, but other embodiments exist that donot have a hardened contact edge 20.

The edges of the notched hammer neck 11 in the third embodiment arenon-parallel with respect to one another, and instead form an hourglassshape. This shape starts just below the notched hammer rod hole 15 andcontinues through the notched hammer neck 11 to the notched hammersecond end 16. This hourglass shape yields a reduction in weight of thenotched hammer 10 and also reduces the vibration of the notched hammer10 during operation.

A forth embodiment of the notched hammer 10 is shown in FIG. 10, whichmost related to the second embodiment of the notched hammer 10 shown inFIG. 8. The fourth embodiment does not include neck voids 11 a. Asshown, the fourth embodiment provides the benefits of increasing thesurface area available for distribution of the opposing forces placed onthe notched hammer rod hole 15 in proportion to the thickness of thenotched hammer neck 11 without using a notched hammer first or secondshoulder 14 a, 14 b. As with some other embodiments disclosed anddescribed herein, the fourth embodiment allows for decreased overallnotched hammer 10 weight from the decreased thickness of notched hammerneck 11 while simultaneously reducing the likelihood of elongation ofthe notched hammer rod hole 15.

A fifth embodiment of the notched hammer is shown in FIG. 11. In thefifth embodiment, the thickness of the notched hammer first end 12,notched hammer neck 11, and notched hammer second end 16 aresubstantially similar. A notched hammer first shoulder 14 a ispositioned around the periphery of the notched hammer rod hole 15 foradditional strength and to reduce elongation thereof, as explained indetail above. Additionally, the fifth embodiment includes a hardenedcontact edge 20. The rounded shape of the notched hammer first end 12strengthens the notched hammer first end 12 by improving thetransmission of hammer rod 8 vibrations away from the notched hammerfirst end 12, through the notched hammer neck 11 to the notched hammersecond end 16. The rounded shape also allows for overall weightreduction of the notched hammer 10. The edges of the notched hammer neck11 are parallel in the fifth embodiment, but they may also be curved tocreate an hourglass shape as previously disclosed for other embodiments.

A sixth embodiment of the notched hammer is shown in FIG. 12. In thisembodiment, notched hammer first and second shoulders 14 a, 14 b arepositioned around the periphery of the notched hammer rod hole 15 toprevent elongation thereof. As with the fifth embodiment, the thicknessof the notched hammer first end 12, notched hammer neck 11, and notchedhammer second end 16 are substantially equal. The sixth embodiment alsoincludes a hardened contact edge 20, and the edges of the notched hammerneck 11 are curved to improve vibration energy transfer as previouslydescribed for similar configurations.

A seventh embodiment of the notched hammer is shown in FIG. 13. Thenotched hammer second end 16 of the seventh embodiment includes aplurality of contact surfaces 22 a, 24 a, and 26 a, which increases theoverall surface area available for contact with the material to becomminuted. The seventh embodiment includes a first, a second, and athird contact surface 22 a, 24 a, and 26 a, respectively, which resultsin four distinct contact points—a first, second, third, and fourthcontact points 22 b, 24 b, 26 b, and 28.

During operation, two of the three contact surfaces 22 a, 24 a, 26 a areworking, depending on the direction of rotation of the notched hammer10. The notched hammer 10 may be used bi-directionally by eitherchanging the direction of rotation of the hammermill assembly 2 or byremoving the notched hammer 10 and reinstalling it facing the oppositedirection. For example, during normal operation in a first direction ofrotation, primarily the first and second contact surfaces 22 a, 24 awill contact the material to be comminuted, and the first and secondcontact points 22 b, 24 b will likely comprise the primary workingareas. Accordingly, the third contact surface 26 a will be the trailingsurface so that the third and fourth contact points 26 b, 28 willexhibit very little wear.

If the direction of rotation of the notched hammer 10 is reversed eitherby reversing the direction of rotation of the hammermill assembly 10 orbe reinstalling each notched hammer 10 in the opposite orientation,primarily the second and third contact surfaces 24 a, 26 a will contactthe material to be communicated, and the third and fourth contact points26 b, 28 will likely comprise the primary working areas. Accordingly,the first contact surface 22 a will be the trailing surface so that thefirst and second contact points 22 b, 24 b will likely exhibit verylittle wear.

The first, second, and third contact surfaces 22 a, 24 a, 26 a aresymmetrical with respect to the notched hammer 10 in the seventhembodiment. In the seventh embodiment, the linear distance from thecenter of the notched hammer rod hole 15 to the first, second, third,and fourth contact points 22 b, 24 b, 26 b, 28, respectively, is equal.However, in other embodiments not pictured herein those distances may bedifferent, or the contact surfaces 22 a, 24 a, 26 a, and/or the contactpoints 22 b, 24 b, 26 b, 28 may be different. In such embodiments thecontact surfaces 22 a, 24 a, 26 a are not symmetrical. In still otherembodiments not pictured herein, the notched hammer 10 includes only twocontact surfaces 22 a, 24 a, or more than three contact surfaces.Accordingly, the precise number of contact surfaces used in anyembodiment of the notched hammer 10 in no way limits the scope of thenotched hammer 10.

In the seventh embodiment, the thickness of the notched hammer first end12, notched hammer neck 11, and notched hammer second end 16 issubstantially equal. Furthermore, a hardened contact edge 20 has beenwelded to the notched hammer second end 16 to cover the first, second,and third contact surfaces 22 a, 24 a, 26 a.

An eighth embodiment of the notched hammer 10 is shown in FIG. 14. Thisembodiment is similar to the seventh embodiment in that notched hammersecond end 16 of the eighth embodiment includes three distinct contactsurfaces 22 a, 24 a, 26 a, and four distinct contact points 22 b, 24 b,26 b, 28. However, the notched hammer second end 16 in the eighthembodiment also includes a plurality of edge pockets 29. Each edgepocket 29 is a cutaway portion placed one of the contact surfaces 22 a,24 a, 26 a. In the eighth embodiment two edge pockets 29 are positionedon the notched hammer second end 16 symmetrically about either side ofthe second contact surface 24 a. In other embodiments, the edge pockets29 are not symmetrically positioned on the notched hammer second end 16,and the number of edge pockets 29 in no way limits the scope of thenotched hammer 10. The edge pockets allow temporary insertion of“pocketing” of the material to be comminuted during rotation of thehammermill assembly 2 to increase loading upon the contact surfaces 22a, 24 a, 26 a, and thereby increase the contact efficiency between thenotched hammer 10 and the material to be comminuted.

The depth of each edge pocket 29 may be proportional to the differencebetween the hammer swing length and the distance from the center of thenotched hammer rod hole 15 to the first and third contact surfaces 22 a,26 a. In many applications the depth of the edge pocket 29 is from 0.25to twice the thickness of the notched hammer first end 12. The shape ofthe edge pocket 29 may be rounded, as shown in FIG. 14, or it may beangular in embodiments not pictured herein. Furthermore, the edgepockets 29 may be tapered so that the thickness thereof is not constant.The eight embodiment includes a hardened contact edge 20. It alsoincludes notched hammer first and second shoulders 14 a, 14 b, and theedges of the notched hammer neck 11 are curved so that the notchedhammer 10 is shaped similar to an hourglass.

A ninth embodiment of the notched hammer 10 is shown in FIG. 15. In thisembodiment, the thickness of the notched hammer first end 12, notchedhammer neck 11, and notched hammer second end 16 are substantiallyequal. The ninth embodiment includes notched hammer first and secondshoulders 14 a, 14 b positioned around the periphery of the notchedhammer rod hole 15.

However, unlike other embodiments previously described and disclosedherein, the notched hammer first and second shoulders 14 a, 14 b in theninth embodiment are not symmetrical with respect to the notched hammerrod hole 15. This allows for overall weight and material reduction ofthe notched hammer 10 while still providing the benefits ofreinforcement around the periphery of the notched hammer rod hole 15provided by notched hammer shoulders 14 a, 14 b as previously describedin detail. The ninth embodiment also includes a hardened contact edge20, and the edges of the notched hammer neck 11 are curved.

The various features and or elements that differentiate one embodimentof the notched hammer 10 from another embodiment may be added or removedfrom various other embodiments to result in a nearly infinite number ofembodiments. Whether shown in the various figures herein, allembodiments may include a notched hammer first shoulder 14 a alone or incombination with a notched hammer second shoulder 14 a having aninfinite number of configurations, which may or may not be symmetricalwith one another and/or the notched hammer rod hole 15. Furthermore, anyembodiment may have notched hammer first and/or second shoulders 14 a,14 b on both sides of the notched hammer 10.

Other features/configurations that may be included on any embodimentsalone or in combination include: (1) curved or straight edges on thenotched hammer neck 11; (2) reduced thickness of the notched hammer neck11 with respect to the notched hammer first end 12 and/or notched hammersecond end 16; (3) curved or angular notched hammer first ends 12; (4)hardened contact edges 20; (5) neck voids 11 a; (6) multiple contactpoints; (7) multiple contact surfaces; (8) edge pockets 29; and, (9)multiple blades, which is described in detail below, or any combinationsthereof. Furthermore, any embodiment may be bidirectional. Anyembodiment of the notched hammer 10 may be heat treated if such heattreatment will impart desirable characteristics to the notched hammer 10for the particular application.

In embodiments of the notched hammer 10 having a notched hammer neck 11that is reduced in width (i.e., wherein the edges are curved) orthickness, it is contemplated that the notched hammer 10 will bemanufactured by forging the steel used to produce the notched hammer 10.This is because forging typically in a finer grain structure that ismuch stronger than casting the notched hammer 10 from steel or rollingit from bar stock as found in the prior art. However, the notched hammer10 is not so limited by the method of construction, and any method ofconstruction known to those of ordinary skill in the art may be usedincluding casting, rolling, stamping, machining, and welding.

Another benefit of some of the embodiments of the notched hammer 10 isthat the amount of surface area supporting attachment of the notchedhammer 10 to the hammer rod 8 is dramatically increased. This eliminatesor reduces the wear or grooving of the hammer rod 8 caused by rotationof the notched hammer 10 during use. The ratio of surface area availableto support the notched hammer 10 to the weight and/or overall thicknessof the notched hammer 10 may be optimized with less material usingvarious embodiments disclosed herein. Increasing the surface areaavailable to support the notched hammer 10 on the hammer rod 8 whileimproving securement of the notched hammer 10 to the hammer rod 8 alsoincreases the amount of material in the notched hammer 10 available toabsorb or distribute operational stresses while still providing thebenefits of the free-swinging hammer design (i.e., recoil tonon-destructible foreign objects).

Embodiments of the notched hammer 10 having only a notched hammer firstshoulder 14 a or notched hammer first and second shoulders 14 a, 14 b(oriented either non-symmetrical with respect to the notched hammer rodhole 15, such as the ninth embodiment shown in FIG. 15 or symmetrical,such as the third, sixth, or eighth embodiments, shown in FIGS. 9, 12,and 14, respectively) may be especially useful with the rod hole notch15 a. In such embodiments it is contemplated that the thickness of thenotched hammer first and second shoulders 14 a, 14 b will be 0.5 inchesor greater, but may be less for other embodiments.

It should be noted that the present invention is not limited to thespecific embodiments pictured and described herein, but is intended toapply to all similar apparatuses for improving hammermill hammerstructure and operation. Modifications and alterations from thedescribed embodiments will occur to those skilled in the art withoutdeparture from the spirit and scope of the notched hammer 10.

3. Illustrative Embodiments of Multiple Blade Hammer

Several exemplary embodiments of a multiple blade hammer 30 will now bedescribed. The preferred embodiment will vary depending on theparticular application for the multiple blade hammer 30, and theexemplary embodiments described and disclosed herein represent just someof an infinite number of variations to the multiple blade hammer 30 thatwill naturally occur to those skilled in the art.

A perspective view of a first embodiment of a multiple blade hammer 30is shown in FIG. 16. The first embodiment is a metallic-based multipleblade hammer 30 for use in a rotatable hammermill assembly 2 as shown inFIGS. 1-3. Other embodiments of the multiple blade hammer 30 for usewith types of hammermill assemblies other than that shown and describedherein are included within the scope of the multiple blade hammer 30.

The multiple blade hammer 30 includes a multiple blade hammer first end32 and a multiple blade hammer second end 36, which are connected to oneanother via a multiple blade hammer neck 11. The multiple blade hammer30 in the first embodiment includes a multiple blade hammer rod hole 35formed in the multiple blade hammer first end 32. Multiple blade hammerfirst and second shoulders 34 a, 34 b both surround the multiple bladehammer rod hold 35, which is shown most clearly in FIGS. 16 and 17. Inthis respect, the multiple blade hammer first end 32 is configured in avery similar manner to the notched hammer first end 12 in the ninthembodiment thereof, which is shown in FIG. 15. Accordingly, the multipleblade hammer first and second shoulders 34 a, 34 b in the firstembodiment of the multiple blade hammer 30 are not symmetrical withrespect to the multiple blade hammer rod hole 35.

In other embodiments of the multiple blade hammer 30 not picturedherein, the multiple blade hammer first and second shoulders 34 a, 34 bmay be symmetrical with respect to the multiple blade hammer rod hole35. In such embodiments of the multiple blade hammer 30, the multipleblade hammer first end 32 would be configured in a manner similar to thenotched hammer first end 12 in the third embodiment thereof, which isshown in FIG. 9. In other embodiment of the multiple blade hammer 30 notpictured herein, only a first multiple blade hammer shoulder 34 a maysurround the multiple blade hammer rod hole 35. In such embodiments ofthe multiple blade hammer 30, the multiple blade hammer first end 32would be configured in a manner similar to the notched hammer first end12 in the first embodiment thereof, which is shown in FIG. 5. In stillother embodiments of the multiple blade hammer 30 not pictured herein,the multiple blade hammer neck 31 is reduced in thickness compared tothe thickness of the multiple blade hammer first end 32. In suchembodiments of the multiple blade hammer 30, the multiple blade hammerfirst end 32 would be configured in a manner similar to the notchedhammer first end 12 in the second embodiment thereof, which is shown inFIG. 8. Accordingly, it will become apparent to those skilled in the artin light of the present disclosure that the multiple blade hammer firstend 32 may include a multiple blade hammer first shoulder 34 a and/or amultiple blade hammer second shoulder 34 b, both of which may be in anyconfiguration/orientation disclosed for the notched hammer 10.

The multiple blade hammer second end 36, which is the contact end, inthe first embodiment includes a first, second, and third blade 37 a, 37b, 37 c. These three blades 37 a, 37 b, 37 c provide for three distinctcontact surfaces in the axial direction, which is best seen in FIG. 16.The multiple blade hammer second end 36 provides for contact anddelivery of momentum to material to be comminuted. The multiple bladehammer second end 36 includes at least two blades 37 a, 37 b, and in thefirst embodiment pictured herein includes three blades 37 a, 37 b, 37 c.Accordingly, the multiple blade hammer 30 may be configured with two ormore blades 37 a, 37 b, 37 c depending on the particular application,and the scope of the multiple blade hammer 30 extends to any hammerhaving two or more blades 37 a, 37 b, 37 c. The at least two blades 4have combined width greater than the width of the multiple blade hammerfirst end 32. The distance between the blades 37 a, 37 b, 37 c will varydepending on the specific application of the multiple blade hammer 30,and in the first embodiment the distance between the blades 37 a, 37 b,37 c is approximately equal to the thickness of the blades 37 a, 37 b,37 c, which is approximately one-fourth of an inch. However, theparticular dimensions and/or orientation of the blades 37 a, 37 b, 37 cis in no way limiting.

In other embodiments not pictured herein, the multiple blade hammer 30structure may undergo further manufacturing work and have tungstencarbide welded to the periphery of each of the hammer blades 37 a, 37 b,37 c for increased hardness and abrasion resistance. Furthermore, themultiple blade hammer first end 32, second end 36, and neck 31 may beheat-treated for hardness. It is contemplated that in many embodimentsof the multiple blade hammer 30 it will be beneficial to construct themultiple blade hammer 30 using forging techniques. However, the scope ofthe multiple blade hammer 30 is not so limited, and other methods ofconstruction known to those of ordinary skill in the art may be usedincluding casting, machining and welding.

In other embodiments of the multiple blade hammer 30 not picturedherein, the multiple blade hammer 30 may have neck voids 11 a placed inthe multiple blade hammer neck 31. In still other embodiments of themultiple blade hammer 30 not pictured herein, the thickness of themultiple blade hammer neck 31 may be less than the thickness of eitherthe multiple blade hammer first end 32 or second end 36. In suchembodiments of the multiple blade hammer 30, the multiple blade hammerfirst end 32 and neck 31 would be configured substantially similar tothe notched hammer first end 12 and 11 in the fourth embodiment thereof,which is shown in FIG. 10.

In still other embodiments of the multiple blade hammer 30 not picturedherein, each blade 37 a, 37 b, 37 c may be configured to have more thanone distinct contact point. In such embodiments of the multiple bladehammer 30, each blade 37 a, 37 b, 37 c would be configured substantiallysimilar to the notched hammer second end 16 in the seventh embodimentthereof, which is shown in FIG. 13. Edge pockets 29 may be positioned inany of the blades 37 a, 37 b, 37 c in variations of such embodiments,the configuration of which is not limiting to the scope of the multipleblade hammer 30 in any way, and may vary in a manner previouslyexplained for the eighth embodiment of the notched hammer 10.

A second embodiment of the multiple blade hammer 30 is shown in FIG. 18.In the second embodiment the multiple blade hammer rod hole 35 is formedwith at least one rod hole notch 15 The at least one rod hole notch 15 atransverses the length of the multiple blade hammer rod hole 35 and isaligned with the multiple blade hammer neck 31. As shown in FIG. 18, thelongitudinal axis of the rod hole notch 15 a is parallel with thelongitudinal axis of the multiple blade hammer rod hole 35, but may havedifferent orientations in embodiments not pictured or described herein,such as an embodiment wherein the rod hole notch 15 a is not parallel tothe longitudinal axis of the multiple blade hammer rod hole 15.Furthermore, the cross-sectional shape of the rod hold notch 15 a may beany shape, such as circular, oblong, angular, or any other shape knownto those skilled in the art. Additionally, the cross-sectional shape ofthe rod hole notch 15 a may vary along its length.

The various features and or elements that differentiate one embodimentof the multiple blade hammer 30 from another embodiment may be added orremoved from various other embodiments to result in a nearly infinitenumber of embodiments. Whether shown in the various figures herein, allembodiments may include a multiple blade hammer first shoulder 34 aalone or in combination with a multiple blade hammer second shoulder 34a having an infinite number of configurations, which may or may not besymmetrical with one another and/or the multiple blade hammer rod hole35. Furthermore, any embodiment may have multiple blade hammer firstand/or second shoulders 34 a, 34 b on both sides of the multiple bladehammer 30.

Other features/configurations that may be included on any embodimentsalone or in combination include: (1) curved or straight edges on themultiple blade hammer neck 31; (2) reduced thickness of the multipleblade hammer neck 31 with respect to the multiple blade hammer first end32 and/or any blades 37 a, 37 b, 37 c; (3) curved or angular multipleblade hammer first ends 32; (4) hardened contact edges 20 positioned onand/or adjacent to the blade edges 38; (5) neck voids 11 a; (6) multiplecontact points on any blade 37 a, 37 b, 37 c; (7) multiple contactsurfaces; (8) edge pockets 29; and, (9) multiple blades 37 a, 37 b, 37c, which is described in detail below, or any combinations thereof.Furthermore, any embodiment may be bidirectional. Any embodiment of themultiple blade hammer 30 may be heat treated if such heat treatment willimpart desirable characteristics to the multiple blade hammer 30 for theparticular application.

In embodiments of the multiple blade hammer 30 having a multiple bladehammer neck 31 that is reduced in width (i.e., wherein the edges arecurved) or thickness, it is contemplated that the multiple blade hammer30 will be manufactured by forging the steel used to produce themultiple blade hammer 30. This is because forging typically in a finergrain structure that is much stronger than casting the multiple bladehammer 30 from steel or rolling it from bar stock as found in the priorart. However, the multiple blade hammer 30 is not so limited by themethod of construction, and any method of construction known to those ofordinary skill in the art may be used including casting, rolling,stamping, machining, and welding.

Another benefit of some of the embodiments of the multiple blade hammer30 is that the amount of surface area supporting attachment of themultiple blade hammer 30 to the hammer rod 8 is dramatically increased.This eliminates or reduces the wear or grooving of the hammer rod 8caused by rotation of the multiple blade hammer 30 during use. The ratioof surface area available to support the multiple blade hammer 30 to theweight and/or overall thickness of the multiple blade hammer 30 may beoptimized with less material using various embodiments disclosed herein.Increasing the surface area available to support the multiple bladehammer 30 on the hammer rod 8 while improving securement of the multipleblade hammer 30 to the hammer rod 8 also increases the amount ofmaterial in the multiple blade hammer 30 available to absorb ordistribute operational stresses while still providing the benefits ofthe free-swinging hammer design (i.e., recoil to non-destructibleforeign objects).

Embodiments of the multiple blade hammer 30 having only a multiple bladehammer first shoulder 34 a or multiple blade hammer first and secondshoulders 34 a, 34 b (oriented either non-symmetrical with respect tothe multiple blade hammer rod hole 35 or symmetrical) may be especiallyuseful with the rod hole notch 15 a. In such embodiments it iscontemplated that the thickness of the multiple blade hammer first andsecond shoulders 34 a, 34 b will be 0.5 inches or greater, but may beless for other embodiments.

It should be noted that the present invention is not limited to thespecific embodiments pictured and described herein, but is intended toapply to all similar apparatuses for improving hammermill hammerstructure and operation. Modifications and alterations from thedescribed embodiments will occur to those skilled in the art withoutdeparture from the spirit and scope of the multiple blade hammer 30.

4. Illustrative Embodiments of Dual-Blade Hammer

Referring now to the drawings, wherein like reference numerals designateidentical or corresponding parts throughout the several views, FIG. 19provides a perspective view of one embodiment the dual-blade hammer 110.The embodiment of the dual-blade hammer 110 pictured herein includes aconnector end 120, a contact end 140, and a neck 130 positioned betweenthe connector end 120 and contact end 140. In the embodiment picturedherein, the neck first end 132 is affixed to the connector end 120 andthe neck second end 134 is affixed to the contact end 140.

The connector end 120 in the embodiment pictured herein is formed with arod hole 122 therethrough. The rod hole 122 may be formed with a notch126 therein as well, as best shown in FIG. 20. The rod hole 122 servesto pivotally attach the dual-blade hammer 110 to a hammer pin or rod(neither shown) of a hammermill assembly. Hammer pins and rods used inhammermill assemblies and their operation are not further describedherein for purposes of clarity, but are well known to those skilled inthe art.

The connector end 120 may also include a first shoulder 124 a positionedaround the periphery of the rod hole 122. The notch 126 may protrudeinto the first shoulder 124 a, as shown in the embodiment of thedual-blade hammer 110 pictured in FIGS. 19 and 20. A second shoulder 124b may also be positioned around a portion of the periphery of the firstshoulder 124 a. In the embodiment pictured herein, the second shoulder124 b encompasses approximately one-half of the periphery of the firstshoulder and is positioned opposite the area of the first shoulder 124 ain which the notch 126 is formed.

As shown herein, the first shoulder 124 a is not generally circular inshape, but rather it is generally triangular in shape with a roundedvertex adjacent the notch 126, and the thicknesses of the first andsecond shoulders 124 a, 124 b are approximately equal. Thisconfiguration allows for discrepancies in the location of the rod hole122 to account for machining differences within the hammermill. That is,the precise location of the rod hole 122 and notch 126 may be adjustedby a predetermined amount along the length of the connector end 120 toadjust the swing length of the dual-blade hammer 110. That is, an areaexists in the connector end 120 in which the rod hole 122 may bepositioned such that the rod hole 122 is within the periphery of thefirst and second shoulders 124 a, 124 b. In such a case, the dual bladehammer 110 would be formed without a rod hole 122, and the rod hole 122would be added just prior to installation in a hammermill so that theswing length of the dual-blade hammer 110 could be precisely set. Thearea in which the rod hole 122 could be formed may have a different sizein one embodiment of the dual-blade hammer 110 to the next, and theamount of swing-length adjustment will also depend on the size of therod hole 122. However, it is contemplated that the most criticaldimension of this area will be along the length of the dual-blade hammer110, and the amount of adjustment in that dimension may be as small oras large as required by the tolerances of the hammermill, and istherefore in no way limiting to the scope of the dual-blade hammer 110.

In the pictured embodiment of the dual-blade hammer 110, a line ofsymmetry exists along the length of the dual-blade hammer from the viewshown in FIG. 20. This line of symmetry bisects the rod hole 122 andnotch 126, and passes through the vertex of the first shoulder 124 a. Inother embodiments not pictured herein, the first shoulder 124 a mayextend further down the neck 130 than it does in the illustrativeembodiment, allowing even more adjustment in the swing length of thedual-blade hammer 110. Alternatively, the first shoulder 124 a may begenerally semi-circular in shape, such as in the notched hammer firstshoulder 14 a shown in FIG. 15. Accordingly, the specific shape and/orconfiguration of the first shoulder 124 a and/or second shoulder 124 bin no way limit the scope of the dual-blade hammer 110 as disclosed andclaimed herein.

The first and/or second shoulders 124 a, 124 b provide increasedstrength and longevity to the dual-blade hammer 110 in manyapplications, as is well known to those skilled in the art. In theembodiment pictured herein, both the first and second shoulders 124 a,124 b are positioned on both sides of the rod hole 122, which is bestshown in FIG. 21. However, in other embodiments not pictured herein,either the first or second shoulder 124 a, 124 b may be positioned ononly one side of the rod hole 122. The optimal dimensions of both thefirst and second shoulders 124 a, 124 b will vary depending on thespecific application of the dual-blade hammer 110, and are therefore inno way limiting to the scope of the dual-blade hammer 110. In theembodiment pictured herein, the thickness of both the first and secondshoulders 124 a, 124 b is 0.75 inches.

In the embodiments pictured herein, the connector end 120 is rounded, asbest shown in FIGS. 19, 20, and 22. In the embodiment of the dual-bladehammer 110 pictured herein, the outer diameter of the connector end is2.5 inches. However, in other embodiments not pictured herein, theconnector end 120 may have other shapes, such as rectangular,triangular, elliptical, or otherwise without departing from the spiritand scope of the dual-blade hammer 110 as disclosed herein. Furthermore,the relative dimensions and angles of the various elements of thedual-blade hammer 110 may be adjusted for the specific application ofthe dual-blade hammer 110, and therefore an infinite number ofvariations of the dual-blade hammer 110 exist, and such variations willnaturally occur to those skilled in the art without departing from thespirit and scope of the dual-blade hammer 110.

As best shown in FIG. 20, the neck edges 138 of the embodiment of thedual-blade hammer 110 pictured herein are non-linear. In the embodimentpictured herein, curvature of both neck edges 138 is derived from acircle having a radius of eighteen inches. However, the preciseorientation and/or configuration of the neck edges 138 are in no waylimiting in scope. Accordingly, in other embodiments of the dual-bladehammer 110 not pictured herein the neck edges 138 may be linear. Theoptimal width, curvature, and configuration of the neck 30 will varydepending on the specific application of the dual-blade hammer 110,which may depend on the type of material to be comminuted.

The neck 130 of the dual-blade hammer 110 includes at least one neckrecess 136, which is best shown in FIGS. 19, 20, and 22. The neck recess136 in the embodiment pictured herein is generally rectangular in shapewith rounded corners, but may have other shapes in other embodiments notshown herein. The curved portions of the neck recess 136 pictured hereinare derived from circles having radii of three and one-half inches,which may be more or less in other embodiments not pictured herein. Oneor more neck recesses 136 may be formed in each side of the neck 130,and the optimal number, orientation, and configuration of neck recesses136 will depend on the specific application of the dual-blade hammer110. In the embodiment pictured herein, the dual-blade hammer 110includes two identical neck recesses 136 symmetrically (with respect tothe orientation shown in FIG. 21) positioned on each side of the neck130.

In the embodiment pictured herein, each neck recess 136 protrudes intothe neck 130 by 0.075 inches, such that the width of the neck 130between the two neck recesses 136 is 0.1 inch.

Accordingly, the thickness of the neck 130 at a position thereof inwhich no neck recesses 136 protrude is 0.25 inches. However, thedimensions of the neck 130, including the thickness thereof adjacent toneck recesses 136, and the dimensions, configuration, and/or placementof neck recesses 136 is in no way limiting to the scope of thedual-blade hammer 110. The dual-blade hammer 110 may have any number ofneck recesses 136 (e.g., a single neck recess 136 on one side of theneck 130, multiple neck recesses 136 on one side of the neck 130,multiple recesses 136 on both sides of the neck 130, etc.). Furthermore,the neck recesses 136 may have any shape without departing from thespirit and scope of the dual-blade hammer 110 as disclosed and claimedherein. In other embodiments of the dual-blade hammer 110 not picturedherein the neck recess(s) 136 may extend through the neck 130. In suchembodiments, the neck recess(s) 136 would appear as voids positioned inthe neck 130. Several such embodiments of such voids are disclosed inU.S. Pat. No. 7,559,497, which is incorporated by reference herein inits entirety.

The neck second end 134 is affixed to the contact end 140. The contactend 140, which delivers energy to the material to be comminuted, mayhave an infinite number of configurations, the optimal of which willdepend on the particular application of the dual-blade hammer 110. Forexample in embodiments not pictured herein, the contact end 140 may becomprised of a single contact surface with multiple contact points, orit may be configured with multiple contact surfaces having multiplecontact points. Certain embodiments of the contact end 140 that may beincluded with the dual-blade hammer 10 are disclosed in U.S. patentapplication Ser. No. 12/398,007, which is incorporated by referenceherein in its entirety.

In the embodiment pictured herein, the contact end 140 is formed with afirst contact surface 142 a and a second contact surface 142 b, whereinthe two contact surfaces 142 a, 142 b are separated from one another byan interstitial area 144. Other embodiments of the dual-blade hammer 110may include a weld-hardened edge on one or more of the contact surfaces142 a, 142 b. In the embodiment of the dual-blade hammer 110 picturedherein, the width of the contact end 140 is two inches, and the overallthickness of the contact end is 0.75 inches. The thickness of theinterstitial area 144 is 0.1 inches. However, as stated above, thecontact end 140 may take on any orientation and/or configuration withoutdeparting from the spirit and scope of the dual-blade hammer 110 asdisclosed and claimed herein.

The materials used to construct the connector end 120, first or secondshoulder 124 a, 124 b, neck 130, and contact end 140 will vary dependingon the specific application for the dual-blade hammer 110. Certainapplications will require a high tensile strength material, such assteel, while others may require different materials, such ascarbide-containing alloys. Accordingly, the above-referenced elementsmay be constructed of any material known to those skilled in the art,which material is appropriate for the specific application of thedual-blade hammer 110, without departing from the spirit and scopethereof.

Other methods of using the dual-blade hammer 110 and embodiments thereofwill become apparent to those skilled in the art in light of the presentdisclosure. Accordingly, the methods and embodiments pictured anddescribed herein are for illustrative purposes only. The dual-bladehammer 110 also may be used in other manners, and therefore the specifichammermill in which the dual-blade hammer 110 is used in no way limitsthe scope of the dual-blade hammer 110.

It should be noted that the dual-blade hammer 110 is not limited to thespecific embodiments pictured and described herein, but is intended toapply to all similar apparatuses for reducing the weight of acommuniting instrument while retaining the strength thereof.Modifications and alterations from the described embodiments will occurto those skilled in the art without departure from the spirit and scopeof the dual-blade hammer 110.

1. A hammer for use in a rotatable hammermill assembly, said hammercomprising: a. a connector end; b. a rod hole positioned in saidconnector end; c. a neck having a first and second end, said neck firstend connected to said connector end; d. a contact end connected to saidneck second end; and e. a neck recess formed in said neck between saidneck first and second ends.
 2. The hammer according to claim 1 whereinsaid hammer further comprises a plurality of welds affixed to saidcontact end.
 3. The hammer according to claim 1 wherein said hammerfurther comprises a first shoulder positioned around said rod hole. 4.The hammer according to claim 1 wherein said hammer further comprises asecond shoulder positioned around a portion of said first shoulder. 5.The hammer according to claim 1 wherein said contact end is furtherdefined as comprising: a. a first contact surface; b. an interstitialarea adjacent said first contact surface; and c. a second contactsurface adjacent said interstitial area.
 6. The hammer according toclaim 1 wherein said neck is further defined as having neck edges thatare not linear.
 7. The hammer according to claim 1 wherein said hammeris further defined as being forged.
 8. The hammer according to claim 1wherein each side of said hammer comprises a neck recess.
 9. A hammerfor use in a rotatable hammermill assembly, said hammer comprising: a. aconnector end; b. a rod hole positioned in said connector end; c. afirst shoulder surrounding a portion of said rod hole; d. a secondshoulder surrounding a portion of said rod hole; e. a neck having afirst and second end, said neck first end connected to said connectorend; f. a contact end connected to said neck second end; and g. a neckrecess formed in said neck between said neck first and second ends. 10.The hammer according to claim 9 wherein said first shoulder is furtherdefined as being generally triangular in shape, wherein the vertex ispointed toward said contact end.
 11. The hammer according to claim 10wherein said hammer further comprises a notch, and wherein said notch ispositioned in said first shoulder.
 12. The hammer according to claim 11wherein said contact end is further defined as comprising: a. a firstcontact surface; b. an interstitial area adjacent said first contactsurface; and c. a second contact surface adjacent said interstitialarea.
 13. The hammer according to claim 12 wherein each side of saidhammer comprises a neck recess.
 14. A hammer for use in a rotatablehammermill assembly, said hammer comprising: a. a connector end; b. afirst shoulder positioned on said connector end; c. a second shouldersurrounding a portion of said first shoulder, wherein said firstshoulder and said second shoulder are configured such that a rod holemay be positioned in said connector end within the periphery of saidfirst shoulder and said second shoulder at various positions along thelength of said hammer; d. a neck having a first and second end, saidneck first end connected to said connector end; and e. a contact endconnected to said neck second end.
 15. The hammer according to claim 14wherein said first shoulder is further defined as being generallytriangular in shape, and wherein the vertex of said first shouldergenerally points toward said contact end.
 16. The hammer according toclaim 15 wherein said contact end is further defined as comprising: a. afirst contact surface; b. an interstitial area adjacent said firstcontact surface; and c. a second contact surface adjacent saidinterstitial area.
 17. The hammer according to claim 16 wherein theperipheries of said first and second shoulders allow for two inches ofadjustment for the placement of the center of a rod hole.
 18. The hammeraccording to claim 17 wherein said hammer further comprises a rod holepositioned in said connector end.
 19. The hammer according to claim 18wherein each side of said hammer comprises a neck recess.
 20. The hammeraccording to claim 19 wherein said hammer further comprises a notch, andwherein said notch is positioned in said first shoulder.